Currently the interest in isothermal forging dies of high strength and metal-metal matrix composite material is quite high. These applications require material that has high strength at temperatures of 1000.degree. C. and above. Because arc cast alloys are very expensive and require more metalworking to develop mechanical properties than do powder metallurgical (P/M) alloys, P/M alloys are used exclusively for isothermal forging dies. However, for high strength fibers intended for use in composites, materials from both methods are being considered. The more expensive arc cast alloys have better chemistry control than the P/M alloys which generally tend to have higher oxygen contents that are detrimental to property development.
Of the currently available alloys that are suitable for these applications, three are listed below in the order of decreasing strength at about 1000.degree. C.:
1. Mo+W+Hf+C --HWM PA1 2. Mo+Hf+C --HCM PA1 3. Mo+Ti+Zr+C --TZM or MT-104